It lasts a total of 20 second PER REST. There are currently a number of spells that grant character immunity for that duration that have more charges
Armor has no effect on deflection. High deflection builds are balanced by extremely low damage.
Currently there are also spammable potions in game that would full heal you. Far more powerful than this ability.
Immunity, really? Not against physical attacks. Being almost unhittable with a single spell even against strong enemies would definately be overpowered.
Potions that fully heal you should be rare, otherwise something's wrong. I find them lame anyway.
Fair enough. But it's a two per rest, short duration spell that against any decent enemy that has a negligible effect.
If you already wear heavy armor and cast AV, things look different though. You might even boost your deflection to untouchable levels. It's I think already a problem, that there are builds with so high deflection that they almost never get hit by certain enemies.
To make AV halfway balanced, it should give diminishing returns I think. That is, if your deflection is very low, it should boost it considerably by perhaps 50 points, and if your deflection is high-end, it should only get boosted by perhaps 15 points or so.
They could penalize the AV using the recovery speed of the armor worn and explain it away as some sort of interference effect.
Wearing a shield could be problematic, because the deflection bonus stacking with AV might be imba. You could say AV is a shield in itself that is not as beneficial if you already have shield, and of course their could be interference too. They could use a formula like deflection = shield + AV/2